Addition is the first basic OPERATION that we have learned as a beginner but here is short cuts methods involved in the Addition.Our Divisibility rules for 1 to 20 is big hit, now it is turn to learn quick addition method. You should teach your elementary child to do quick addition with this simple step by step method. This addition and subtraction will help him/her in mental math tricks too and it will be easy to solve any maths problems regarding addition and subtraction.
Examples of adding numbers which ends with 9 and 8:

685+99=

829+999=

345+9999=

792+888=
Solution for shortcut addition method:
Notes to remember: Whenever you want to add 99, you need to round up 99 to 100 and take away what you are adding (subtract).
Credit: I give all credit to my mom who is my best teacher.